Many techniques have been described by others to extract energy from moving vehicles. See, for example, UK Patent No. 1,332,202 and U.S. Pat. Nos. 4,130,064, 4,238,687, 4,614,875, 4,980,572, and 5,355,674. The methods disclosed by these references involve a vehicle riding over and depressing a treadle or ramp or similar lever because of the weight and momentum of the vehicle. The forced movement of the treadle is then converted into electrical energy by either mechanical linkages or gears coupled to flywheels and/or electrical generators or by pistons or other fluid pumps that drive fluid through a hydraulic motor. The hydraulic motor may be used to rotate an electrical generator or drive some mechanical actuator.
These methods typically impart a significant vertical component of force to the vehicle wheels. Those methods that make no effort to limit this vertical force cause, at least, a bumpy ride or, at worst, an accident due to the dynamic interaction of the vehicle with the vertical forces exerted by the treadle. Many of these inventions incorrectly state or imply that the energy extracted from the moving vehicle is, in some way, a conversion of otherwise unused or wasted energy. All of the methods that extract energy from the moving vehicle must introduce a force that retards the vehicle. Those inventions that recognize this suggest that the invention only be used in locations where the vehicle would otherwise have to apply brakes. Thus some of the retarding energy is utilized instead of being wasted.
One method, which is disclosed in U.S. Pat. No. 4,700,540 (xe2x80x9cthe ""540 patentxe2x80x9d), is designed for railroad applications and creates a fluid pumping action by having the flanges of the wheels successively compress a collapsible tube (roller pump) in a closed-loop hydraulic system. The ""540 patent states that the tube walls and a fluid accumulator should be designed to exert a safe limit of vertical reaction force. The ""540 patent, however, does not provide the magnitude of this limit. The collapsible tube may be compressed by a train coming from either direction because the proposed system includes a bi-directional valve, which must be operated by an approaching train closing one of two switches (one for each direction) so that the system can operate properly. The ""540 patent proposes that such changes as increasing the wheel flange heights by one or two inches would improve performance. However, such a change would have a major economic impact on railroads because of the cost of changing the many wheel sets that are currently in use. For example, in the United States there are about eight million railroad wheels that would have to be replaced.
Known methods proposed by others require a means, such as a spring that is compressed by the action of the vehicle on the treadle (or tube wall) or a weight that is lifted by that action, to provide a restoring force to reset the treadle (or tube wall) to its initial operating position. These methods all store a portion of the energy removed from the vehicle in the form of potential energy and then use that portion of stored energy to reset the device. These means for resetting the device using stored energy require the use of components that complicate the design and increase the likelihood of system failure.
A purpose of this invention is to reduce the vertical dynamic reaction force exerted by an energy converter on railroad vehicles while extracting energy from passing trains. Reduction of this vertical reaction force reduces the probability of an accidental derailment.
Another purpose of this invention is to eliminate the need to store some of the extracted energy for resetting the energy converter system after the passage of each wheel. According to an aspect of this invention, passage of a vehicle wheel is utilized to perform the resetting of the energy conversion system.
It is a further purpose of this invention to provide railroads with a system for extracting energy from a moving train that does not require substantial modification to existing railroad equipment.
An energy extractor in accordance with the principles of the invention may include a pivoting member composed of two elements that are contacted by a railroad wheel as the wheel passes. The pivoting member will be moved from its initial position to a second position as the railroad wheel contacts the first element and then is returned to its initial position as the wheel contacts the second element and passes beyond it. This pivoting motion, which is forced by the passing wheel, may be converted into useful electrical or mechanical energy by any one or more of the many possible means that are well known.
The pivoting member may be disposed to rotate in a horizontal plane, a vertical plane, or in any other plane of rotation that is found to be desirable. Preferably, the pivoting member is disposed in a horizontal plane. In such a configuration, the contact elements preferably reduce the vertical reaction force on each wheel by permitting each contact element to rotate about a horizontal axis. In this way, vertical motion of the rim of the wheel merely rotates the contact member while the wheel exerts a lateral force to push aside the contact member.
Depending upon the desired amount of energy to be extracted from the moving train, a multiplicity of pivoting members may be utilized by placing the pivoting members sequentially along the track. The extraction of energy from the train causes a retarding force to be exerted against each wheel as it is in contact with a pivoting member. For safety considerations, it is preferable to use the same number of pivoting members and associated energy conversion means on each of the two rails. In this way, both wheels of each axle will contact the pivoting members at substantially the same time, thereby minimizing any unbalance of forces that would otherwise tend to skew the axle.
There are regions of railroad track that do not have access to electrical power because they are far from electrical utility lines. Such regions are called xe2x80x9cdark territoryxe2x80x9d in railroad parlance. Motorists at road crossings at grade in dark territory are alerted to the presence of railroad tracks by a static sign, usually in the form of an X (crossbuck), that says xe2x80x9cRailroad Crossing.xe2x80x9d Such signs have been found to be virtually ineffective in preventing accidents. A study by the Federal Railroad Administration, xe2x80x9cSafety of Highway-Railroad Grade Crossings, Vol. II. January, 1996, DOT-VNTSC-FRA-95-12.2,xe2x80x9d found that the crossbuck sign is approximately only one-one hundredth as effective as a flashing warning light in reducing the potential of a grade crossing accident. Gates are more than one thousand times more effective than a crossbuck sign. This report found that the crossbuck sign is barely more effective than nothing at all. If energy extracted from a passing train were used to operate some sort of active warning devices, such as flashing lights, then there may be a significant reduction in the probability of accidents at grade crossings in dark territory.
Additional features and advantages of the invention will be apparent upon reviewing the following detailed description.